Both insitu and exsitu methods to remove contaminates from soils are known. U.S. Pat. No. 4,202,282 is exemplary of exsitu method. In this method, contaminated soil is placed on a conveyer belt and infrared heat is used to drive off gasses from contaminated material. Substantial equipment is required, and either this equipment must be moved to the contaminated site, or the contaminated material must be moved to the location of the remediation equipment. It would be preferable to have a method wherein the equipment is more readily relocated.
U.S. Pat. No. 4,984,594 discloses a method whereby the soil is heated insitu to remove contaminants. Volatile substances in the soil are vaporized by the heat and drawn upward and gathered into a vacuum system where they are condensed in traps for subsequent treatment, or disposal. Soil heating is effected by means of an electric heater that is placed upon the soil surface. The heater is a mesh of electrically-conductive wires, and is in contact with the soil. Heat is transferred into the soil by thermal conduction. Heater blankets for insitu remediation are effective for removing contaminants from a relatively flat surfaces, but soil surfaces are often uneven so that at least some soil must be removed for decontamination. Further, some contaminates are located too deep in soil for remediation by heat injection from the surface.
Heat can be injected to greater depths, for example, by use of radio frequency energy, as suggested in U.S. Pat. No. 4,670,634. Insitu heating can be useful, but it can be difficult to target a specific contaminated region, and even when insitu heating is applied, there may be a volume of contaminated soil that is better removed and treated exsitu. It would be advantageous to have an apparatus to perform this exsitu remediation wherein the equipment is easily transported.
U.S. Pat. No. 5,127,343 suggests a heater tray for exsitu remediation of soil. The tray is shallow and wide and heat is applied radiantly from above the soil. Vapors are drawn through the soil and treated. Although the tray into which the soil is placed is said to be movable by a trailer, the limited depth of the tray results in only a relatively small amount of soil being treatable at one time. The process of spreading contaminated soil into the tray and removing remediated soil, and waiting for the soil to cool sufficiently for handling, is time consuming and labor intensive. It would be desirable to have an apparatus to treat soils exsitu wherein the apparatus is transportable by a trailer, and wherein a greater volume of soil can be treated at one time, and wherein more of the equipment could be used continuously.
It is therefore an object of the present invention to provide an apparatus for treating contaminated soils exsitu wherein the apparatus is readily transportable by a truck or trailer, and wherein a significant volume of contaminated soil can be treated at one time.